I have same problem.. I refused to response because I dislike scammer and have no idea what it is for. I'm deaf and they left msg and say case nbr like you said. Nothing for what it is for as details or etc...
Same as above, have been calling for days, but the last 2 days it's been a lot. My phone says spam so I'm not answering it. Vm says my name and says they have a claim against me and I'm getting sued yada yada.. Btw my vm says my name on it, pretty sure that's where they got my name from because I recall them calling before and the vm just being silent.
Same has happened to me. Although they have called people i know as well. They called again today asking to verify my current resident and employers location, otherwise they'd serve my HR with proper papers...if they know my HR location, why even verify?